A new 97.6-megawatt battery-storage wind power facility is now online in West Virginia. The installation represents the world’s largest lithium-ion-based wind energy storage project and the biggest advanced battery clean energy project in the United States.

Laurel Mountain will deliver 260,000 MWh of clean, flexible power to the grid, helping supply electricity to residents and business in 13 eastern states and the District of Columbia—the largest power market in the world. The farm, built by the wind generation and energy storage wings of global power provider AES Corporation (NYSE: AES), uses 61 GE 1.6 MW wind turbine generators and 32 MW of A123 Systems energy storage devices.

Although the technology is still in the early stages and carries a hefty price tag (AES didn’t disclose the cost of the project, but industry experts estimate it cost $25 million), its use is gaining traction.

The ability to regulate renewable power is becoming increasingly important to grid operators, who say that the option of storing wind and solar output is potentially the most cost-effective way to address the problem of fluctuations in power supply and demand.

AES, which last past spring snapped up its Ohio-based rival DPL Inc. for $3.5 billion, is developing more than 500 megawatts of advanced energy storage. The company is currently operating and building 72 megawatts of grid-scale storage, including a 12 MW regulation and reserve project in Chile and an 8 MW battery system in the New York State.